Research Division Seminar
Is the riddle of the astronomical Li origin solved?

Abstract

Lithium is a key   element which plays an important role in  astronomy  as well as everyday human life.  Nevertheless it is probably the only element whose astronomical origin is still a mystery.  A fraction of  about 30% of what is measured today was  made in the first 3 minutes of the Universe and about 10% is  made  by spallation  reactions of  cosmic rays with the atoms in the interstellar medium. However, as stars burn  Li in their hot interiors and what makes the remaining ~60%  is still unknown.  The recent detections of   ⁷Li and ⁷Be in the outburst of   classical novae is a landmark in the solution of this long standing mystery. The discovery   confirms a theoretical speculation  made about 50 years ago    but  which was never  supported by observations.   Since then  the  presence of Be-7 has been confirmed to be ubiquitous in about a dozen classical novae and very recently also in the  recurrent nova RS Oph that blew out in August 2021.  However, the observed values show  tension with theory  being one order of magnitude greater than predictions.  Detailed Li Galactic chemical evolution models   assuming the "observed" yields  show that indeed  Novae could  be the long sought  source for the Galactic  ⁷Li.